Typically screws are required to attach wall battens. Several challenges may exist that are associated with screws being used to attach battens inside a cleanroom. For example, the cost of the wall, including installation, is always of great concern particularly in a competitive bid situation. By eliminating the screws used to attach the battens, then the screw holes on the battens, the labor to attach the screws and the screws themselves may also be eliminated thus reducing the final cost of the wall.
Cleanroom floor panels are typically perforated and/or grated to provide an airflow path for the constant recirculation of filtered air through the cleanroom, which is essentially what creates a “clean” room. In addition, installers are generally required to wear full cleanroom “bunny” suits with double-gloved hands during the installation process. This may greatly increase the likelihood that a screw or screws will be dropped having the potential of falling through the grated floor and falling as much as three stories below onto highly sensitive equipment.
Harmful particulates may be generated every time a screw is screwed into and out of an aluminum screw slot and every time a new hole is predrilled for a screw. Screw slots can typically only be used a limited number of times before the part using the screw slot needs to be replaced because the screw will no longer stay in the galled screw slot.
The manufacturing of semiconductors is highly sensitive. In addition, the life cycle of semiconductors is extremely volatile. When prices are good and the process is running well semiconductor manufacturers must “strike while the iron is hot.” Semiconductor manufacturers typically do not tolerate lengthy interruptions or delays of their manufacturing process.
Cleanroom wall heights are currently 12′-0″ to 16′-0″ tall. This means that for every 4 linear feet of wall 18 to 22 screws are typically installed atop scaffolding. This type of installation is a lengthy process. A solution to this problem may be to provide a wall system that creates the least amount of disruption to their business. By eliminating the screws required to install the wall the install rates for the wall may be significantly improved.
Each time an installer enters the cleanroom they must go through an elaborate gowning process. If for any reason the installer must exit the cleanroom they must pass through the same elaborate gowning process in reverse. Tools, wall appurtenances, hardware, etc. must also pass through an elaborate wipe down process before entering the cleanroom. Therefore, it may be an advantage to reduce the number of parts and pieces required to install the wall. For example, if an installer is in full gown and in the cleanroom discovers that a new hole must be drilled, the installer may take up to half an hour to exit the cleanroom, remove the gown, drill the hole, wipe down the batten or stud, put the gown back on, and install the batten. A solution to this problem may be to eliminate the screws because eliminating the screws reduces the number of tools, wall appurtenances, and hardware required to install the wall.
Some cleanroom wall systems are progressive wall systems. Progressive wall systems are serially assembled and disassembled. For example, because the walls are assembled one after another, to remove a single wall panel, all intervening wall panels must also be removed.
Cleanroom walls generally should be smooth, so no ledges are present to collect particulate; cleanable so wipe down of the walls, which happens multiple times per day, removes any particulate present; and fast to erect, because any interruptions to the semiconductor manufacturing process may be devastating. Manufacturers typically want fast installation and modification times.
It may also be desirable to be able to hang shelving and other attachments on a wall system without having the drawbacks involved with systems using screws.